>> Saturday, January 08, 2011

Some quick thoughts this evening....

How about the Saints/ Seahawks game?

Some discrepancies continues with the modeling regarding precip amounts. But, I am going to lay out a few very preliminary accumulation ideas. Please be aware that significant adjustments might need to be made as we approach the event.

For the I-85 corridor from the Upstate of SC all of the way up to the junction with I-77. Snow should begin by Monday morning, and the atmosphere should support all snow for this area until early afternoon at the earliest. After that, the temps aloft warm a bit, and there would be a switch over to sleet and mainly freezing rain. For the GSP area, I will go 3-5" of snow with a glazing of ice after that. For CLT, I will go 2-4," then the glazing. Western areas of the CLT metro could be more toward the 3-5" area.

The Columbia area is a very tough call. There will be a period of snow, but the warming aloft will be quicker down in that area, and a transition to sleet and freezing rain will then occur. The freezing rain potential is much more significant in this area, and at least a quarter inch of ice is quite possible....maybe more.

For the I-40 corridor from GSO to RDU....very very tricky. Precip amounts are a huge question mark. I will go with 2-4" of snow, and then a tenth to maybe a quarter inch of ice in some areas.

Back to the west, this looks like a good snow event for north Mississippi, especially along and north of Hwy 82, and in Alabama north of I-20. Tennessee also looks to see a good snow as well, especially along and south of I-40. I would think a general 3-6" type of snow in many of those areas, and that should carry over into northern Georgia as well. Many spots in the Tennessee Valley area could verify toward the higher end of (or even exceed) that range. I am still quite concerned about the ice potential in central MS, AL, and GA, but precip amounts are a question mark as some modeling is shifting the best precip up into the Tennessee Valley.

Some general ideas as I see it this evening. Be aware some fairly significant adjustments are always possible.

We will see how things look as Sunday unfolds. Keep an eye on the RUC modeling over the next 24 hours, and as we get deeper into Sunday, it becomes increasingly NOWCASTing time....meaning watching radar trends and surface obs instead of models.

Some pretty big model fluctuations and differences continue in terms of amounts of precipitation with our approaching storm system. The 0z run of the GFS put out close to an inch of liquid equivalent precip near and just south and east of Charlotte while the 0z Euro and NAM were much, much less. The 6z GFS came in with about a quarter inch less than the 0z run. The 0z and 6z NAM held the 0.5" QPF line just south of Charlotte. (I just use Charlotte as a good singular point to reference the model differences.)

Winter storm watches are up for a lot of real estate. In the image below, all of the white counties from the Lower Mississippi Valley into the Carolinas are under winter storm watches.

My overall ideas have not changed. This should be a big winter storm for a good chunk of AR, MS, north AL, north Georgia, southern TN, and South Carolina. I feel like this will be a pretty significant event for at least southern NC, but the question marks get larger the farther north you go in NC due to uncertainty with precip amounts.

Below are the Day 2 and Day 3 winter weather maps issued this morning from the HPC.

>> Friday, January 07, 2011

Some thoughts on the early week storm system. Below are two maps outlining my general thoughts on precip type areas. Keep in mind these boundaries are not hard and fast and might be adjusted. Also keep in mind I actually drew them up this morning. After reviewing the 12z data, I might tweak a spot or two, but the overall ideas remain the same.

This is seemingly always the range leading up to winter weather systems where lots of uncertainty seems to develop. I know seeing the QPF numbers continue to gradually wane, especially in NC, is extremely painful for snow fans to watch. I feel your pain. Generally speaking, there has been a trend in the modeling of weakening our southern branch feature every so slightly quicker than some of the previous runs.

Here is something of note....our disturbance is just as strong on the most recent run as it enters the Lower Mississippi Valley that it was on its run 24 hours ago. The quicker weakening takes place as it heads for the upper Southeast. I really think it is just a subtle difference in some energy over the New England states, but equally if not more important is the latest Euro is a little stronger with the next piece of energy in the Rockies.

Just comparing the Euro to the 12z run 24 hours ago, the difference in strength of the system as it enters the Southeast is small, but it is enough to cut the QPF numbers.

This is why I have been stressing, and continue to stress now, to not get wrapped up in QPF numbers. It is not good to get really excited or really down at this point about QPF, even still at this point.

Listen....the southern branch feature will definitely weaken as it approaches the Carolinas. It is a matter of how quickly it will weaken. That is the big question mark for Carolinas precip amounts.

Are the lower precip totals going to be a reality? Possibly, but possibly not. It is simply too soon to know.

This is really the point where I will just keep the forecast ship steady and true as we head into the weekend. I will not change the wording from my overall ideas that I have had out there. The potential for a widespread, significant winter storm from the Lower Mississippi Valley into the Carolinas is still very much there.

Will there be some disappointed people. Yes? Will there be some very happy snow fans? Yes.

Let's give it another 36 hours or so before anybody in the region (from Lower MS Valley to Carolinas) starts cliff-diving or starts the celebrations.

Please give today's edition of the video a watch...I will step you through both today's system and the system early next week.

Two systems in the offing. One is later today and tonight....the other is the much talked about system for early next week.

First off, we basically have a strong clipper that is dropping into the region. I have just seen the 12z NAM, and it is sticking to the idea of painting a very narrow stripe of accumulating snow across the region. This will likely be a strip of accumulating snow only about 50-100 miles across, and it will run in a west to east fashion. Honestly, anywhere from the Hwy 74 corridor to the I-40 is fair game to have this strip set up over you, but right now I would lean more toward the general area around Hwy 64. That is subject to change though. Wherever that strip does set up, a general 1-2" snow could occur. However, if the instability and forcing that the NAM shows does indeed materialize, a few very localized spots might see 3" or 4".

But I can't stress this enough...this will be a narrow and, and many will not see any accumulation at all. The best chance of accumulating snow will be from very late this afternoon through this evening.

System next week....

I don't really have any changes here. Some of the modeling on some runs has backed off a bit on the total precip amounts as the system moves into the Carolinas. That could indeed be the case, but overall I haven't seen a whole lot to lean me away from the idea that this looks like a widespread, high-impact type winter storm for a lot of areas from the Lower Mississippi Valley into the Carolinas.

A little later today, I will post a couple of maps showing the general precip type areas I am going with as of now. Generally speaking, this looks like mainly snow for AR, north MS and AL, TN, north GA, northwestern SC, and much of NC from roughly the I-85 corridor north and west. South and east of that line, there will be an icy mix, and there could be a significant ice event in parts of central MS, AL, GA, and SC.

Again, check back a little later today and I will post some precip type maps.....

>> Thursday, January 06, 2011

After reviewing the latest data through the day, including the entire 12z suite of guidance as well as the 18z NAM, I have seen nothing at all to change the overall concept I have had out there. The bottom line is this....the potential is there for a significant winter storm all of the way from the Red River Valley early Sunday to Arkansas, northern Louisiana, northern and even central Mississippi and Alabama, Tennessee, north Georgia, much of North Carolina, and northern and central South Carolina.

I am growing more and more concerned with the ice potential for areas in central Mississippi, Alabama, Georgia and into central parts of South Carolina. The ingredients are there for a big ice storm in at least parts of those areas. Winds will remain out of the northeast through the duration of the event. Those winds will continue to advect in cold, shallow arctic air. Hopefully for those areas near this zone, either periods of snow or sleet will help to cut down on freezing rain amounts....because if all of the precip were to fall in those areas as freezing rain.....yikes.

North of the icing area is the mainly and all snow area. Right now, I would say that includes Arkansas, the Tennessee Valleys of north Mississippi and Alabama, Tennessee, northern Georgia, the Upstate of South Carolina, and much of North Carolina once north and west of the coastal plain. Significant accumulations of snow are quite possible.

The bottom line is all of the players remain on the field for a big-ticket Deep South and Southeast winter storm Sunday into Monday night and Tuesday morning. I will continue to fine-tune the forecast as we go forward.

Keep in mind that it will be quite cold following the system. Many areas from north Georgia into the Carolinas might not see any significant period of time above freezing until Friday afternoon.

Now, please keep in mind that we are talking about a southern branch upper level low that is still sitting the Pacific Ocean....so lots can change. But as of now, I have not seen anything to cause me to think this is trending away from being a big winter storm in a lot of places.

But, this is all still in the potential category......when I feel confident in near certainties, I will say so and put out accumulation ideas....usually within 48 hours of an event.

Please take time to look at today's video....a graphic is worth a thousand words. I take a long look at the system early next week....

Parts of the region did see a little light snow very early this morning, but that system is exiting stage right. The weather overall through Saturday will be pretty quiet. A few NW flow disturbances will move in and bring the mountains some snow, but aside from a stray flake or two in the Piedmont, not a big deal.

Potential winter storm...

As I have been discussing, early next week is when the potential big-ticket item is. A big upper low, currently in the Pacific off the south California coast, will eject eastward as we head into the weekend and likely be located over the Lower Mississippi Valley Sunday. From there, it will likely weaken a bit as it lifts into the upper Southeast or mid-Atlantic.

All indicators (modeling) are pointing to the possibility of a significant winter storm for parts of northern MS, northern AL, Tennessee, northern GA, northern SC, much of NC up into Virginia and maybe southern New England. But please hear this.....this is still very much in the 'potential' category.

Now, there are some differences in the modeling, but overall, fairly remarkable agreement in the end result. (By the way, please pay no attention to the QPF numbers on modeling at this point).

While there will inevitably be some adjustments on the modeling in coming runs, I don't think we will see wild, huge run-to-run swings like we saw leading up to the Christmas system. We are not 'threading the needle' with the phasing of branches here. It really all comes down to the timing and track of the upper level low currently in the eastern Pacific.

People always ask, and it is my practice to not mention accumulation potential until at least with 48 hours of an event. So, don't ask me for numbers just yet. :-)

I will say this though....this does have the potential to be a significant winter storm for a lot of places in the region. There will likely be an area of significant snow accumulation, and just to the south of that, and area of significant icing is possible before you get into the all-rain zone.

Cold air...

Don't let this get lost in the shuffle. It looks like a big blast of cold air will arrive behind the system by the middle part of next week. This might wind up being the coldest air we have seen thus far this cold weather season.

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>> Wednesday, January 05, 2011

Take a look at the video...I discuss the systems one by one.

Short of time due to work responsibilities this morning, but a few notes. First, the system tonight will bring the chance of some light snow and light rain to the region....mainly rain south of I-85 in SC. This is one of those deals where precip type could be tied directly to precip rates....heavier the precip, more likely to have snow.

The key word for tonight is light. I imagine some areas could see a dusting around the Piedmont, but this does not look like a big deal. Now, NE Georgia and SW NC could do better on that front, but I just don't see a big event out of this for the Piedmont.

Next system could bring a few flakes Thursday night into Friday night. But this one looks pretty light as well.

I am still most interested in the system early next week. I think the GFS is completely clueless as of now. My idea on this is similar to the Canadian and Euro solutions...probably a less extreme version of the Canadian...something similar to the Euro.

I still lean more with a miller a type solution in the later Sunday into Monday time frame. There could wind up being some significant snow somewhere across the region. I am not ready to commit to anything yet, but I am slowly getting slightly more confident.

>> Tuesday, January 04, 2011

Here is today's video....take a look. I discuss the various systems to impact the region in the days ahead...

Tons of uncertainty in the specifics of our forecast over the next two weeks. The overall ideas remain unchanged....cold, and the potential for storm systems from time to time.

The first system to roll through will be late tomorrow night into early Thursday AM. I still think that one could wring out a few snowflakes across the region, but moisture still looks very limited overall this far north.

The next system arrives Friday. This is a strong clipper, and again, I still think this has the chance to produce a little snow even to areas east of the mountains. Not so much for the CLT area....but more toward the Triangle. Please see the video for a little more on this system.

Finally, the models all continue to struggle mightily with the specifics of our system early next week. The Euro and Canadian are on the fast side of the guidance in bringing precip in later Sunday. The GFS is much, much slower.

At this point, I am very cautiously leaning toward the quicker scenario, similar to the Euro. If that were to be the case, and precip later Sunday or Sunday night would probably be in the form of snow for most NC areas. In time, this might evolve into a wintry mix scenario Monday, or a main coastal low could take over in time, indicating more of a snow type of deal. Or, it could be like the GFS, which is MUCH slower....bringing snow in Tuesday!

So, lots of uncertainty, but the pattern remains ripe with potential fun and games.

>> Monday, January 03, 2011

Here is today's edition of the Carolina Weather Video....give it a look.

After a brief reprieve from the very cold December, we are now heading back into a pattern that, frankly, looks a whole lot like what we saw for December. It will be chillier the next few days, and then it looks to get quite cold again by the upcoming weekend.

This pattern is absolutely loaded with potential for winter weather lovers. Will the potential deliver? Who knows....but snow and winter weather fans.....at least you are in the game, right?

Let's take the next few systems one at a time....I will call name them by letters for ease in future discussions....

System 'A'....this is a weakening southern branch system that will move through the region Wednesday night into Thursday morning. The amount of precip that makes it up into NC is very small, if any at all, on most modeling. However, I will say that a few flakes are possible in NC or northern SC early Thursday AM, but the bulk of that precip will probably stay closer to I-10.

System 'B'....This is a potent clipper system that will drop in Friday. The Euro has gone nuts with an exceptionally deep system, but it is more extreme than almost every other model, be it operation or ensemble. This has the potential to be another one of those clippers that produces snow east of the mountains, but tough to get excited over clippers before you can see the whites of their eyes. But be aware there could be a few flakes Friday.

System 'C'....This is a southern branch system that has the potential to bring snow to parts of the South and Southeast around Monday of next week. The Canadian make a 'miller b' system out of this...with a primary low going up west of the mountains and a secondary low popping near the coast. Taken literally, the 0z Canadian is a snow to ice scenario for NC. The Euro and GFS keep this as a 'miller a' system....Gulf low that rides up off the Carolina coast.

I would lean more with the miller a scenario as of now. Be aware that this one could trend in either direction. We could see the huge vortex off the northeast coast squash the system as it approaches the Carolinas. Or, we could see the vortex left out sooner, indicating a farther north track. Or the timing of it could be all off and there be no system in this time frame at all.

And I don't think that is the end of the line....more potential fun and games lies out there later in the month, if the overall pattern holds.

So, nothing at all for snow fans to get fired up about yet, but we are entering a loaded mine field of a pattern.